1. Technical
This patent relates to a mechanical acoustic filter thinner boards manufactured by an erosion etching technique, the mechanical acoustic filter being suitable to be used in electric condenser microphones. The mechanical acoustic filter is to be formed as one or a plurality of boards by erosion etching according to different requirements. Every etched board has corresponding path which, after the boards are assembled, form a sound filtering path.
2. Background
Conventional mechanical acoustic filters are mostly formed by injection molding. However, the present structures can not eliminate the short comings of the acoustic filtering path being too long thus not able to reduce the entire volume of the microphone and unable to reduce high frequency noise.